'Surya's Flame' is imprecisely worded. I'm not sure whether it is intended to inflict additional stress on a successful attack, or to boost the attack roll itself.
If it is the former, then it is notably underpowered, as thematic associations for the purposes of Catch satisfaction are not generally substantial enough to warrant Refresh cost except in extreme cases (eg. All Creatures Are Equal Before God, Sacred Guardian, or variants thereon).